* Avoid redundant string splits
There likely isn't actually more than once to split in the source
strings in these cases, but avoid doing so anyway as we're only
interested in the first.
* Avoid redundant completion output target evaluations
The target is not to be changed while outputting completions, so resolve
it only once.
* Avoid redundant active help enablement evaluations
The enablement state is not to be changed during completion output, so
evaluate it only once.
* Preallocate some slices and maps with known size
* Avoid some unnecessary looping
* Use strings.Builder to construct suggestions
This change adds two features for dealing with flags:
- requiring flags be provided as a group (or not at all)
- requiring flags be mutually exclusive of each other
By utilizing the flag annotations we can mark which flag groups
a flag is a part of and during the parsing process we track which
ones we have seen or not.
A flag may be a part of multiple groups. The list of flags and the
type of group (required together or exclusive) make it a unique group.
Signed-off-by: John Schnake <jschnake@vmware.com>
